Kvarn async

This is a collection of Tokio and other async utilities used in the Kvarn web server.

See doc.kvarn.org for the most up-to-date docs.

lib.rs:

Async bits for web applications.

This includes reading to bytes, a adapter between std's Read trait and tokio's AsyncRead, a [mod@write] module for writing HTTP/1 requests and responses, and a read module for reading HTTP/1 requests and responses.